System of distribution.



L. A. HAWKINS. SYSTEM OF DISTRIBUTION.

APPLICATION FILED MAR. 11. 191a.

1,131,237. Patented Mar. 9, 1915.

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Witnesses Inventor-1 Za /j Laure efLHawkins,

His fittof-neg.

UNITED STATES PATENT OFFICE.

LAURENCE A. HAWKINS, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF-NEW YORK.

' SYSTEM OF DISTRIBUTION.

residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Systems of Distribution, of which the following is a specification.

1 The present invention comprises a system of distribution containing a vapor apparatus, such as a mercury vapor rectifier, and its object is to decrease the liability of discharges of undesired polarity, particularly after an idle period when the tendency of an anode temporarily to become a cathode is increased by the condensation of mercury on or around the anode or anodes.

As disclosed in the Story Patent No. 1,118,880, it has been found advantageous to heat the anodes of a mercury vapor rectifier by means of an auxiliary heater independent of the heating action of the arc to prevent the condensation of mercury on the anodes.

In accordance with my present invention the vapor rectifier is provided with means for automatically heating the anodes when the load current in the rectifier is interrupted or reduced below a certain value, as for example, when the rectifier is used for propulsion in electric railways where it is subject tointermittent service. The anodes are thus kept hot during periods of no load without the necessity of running the heaters continually and thus subjecting them to the danger of overheating during periods of full load or overload.

Another feature of my invention consists in deriving the heating current from the rectifier itself, so that a load is maintained at all times suificient to keep the are going, thus makingit unnecessary to maintain an exciting are or to provide special means for restarting the are after every interrupt on of the load current. This feature of my 1 nvention isnot necessarily limited to ut1l1zing the heating current for maintalning the arc. Any other load could be thrown on instead. But since the heating current 1s requiredjust at the time when the auxil- 'iary load is needed to maintain the arc, simplicity of arrangement and efiiciency of 0peration are conserved by utilizing the heat- ..'.in'"g current as part at least of the auxiliary 1. load. i

Specification of Letters Patent.

Application filed March 11, 1914. Serial No. 823,872.

'1 Patented Mar. 9, 1915.

The accompanying drawing illustrates diagrammatically one-embodiment of my lnvention in connection with a motor control system.

By reference to thisdiagr-am it will be seen that the rectifier 1 receives alternating current from the secondary of a transformer 2, the primary of which is connected between a trolley 3 and ground. The rectifier may be of the metal-walled type described in the above Story patent and in British Patent #15392 of 1913, but my invention is not limited to any particular type of rectifier. The cathode or direct current load circuittis connected to the motors 5 through the usual contactor system, as, for example,

the system shown in Patent No. 687,060 to but preferably they are arranged to be sup-.

plied from the rectifier itself. The circuit comprises the conductors 12, 13, 14, 15 and 16, including a switch 17, which is interlocked with a contact 18 in the motor circuit such that the heater circuit is closed before the motor circuit is opened and vice versa. When the contactor magnet 19 is energized to close its contact in the motor circuit,'the heating circuit is interrupted by the lifting of the switch 17 Thus the contactor 19 which controls the heating circuit may be any contactor of the ordinary motor control system which does not close until after the motor circuit is closed and which remains closed as long as the master controller is in running position. Thus, for instance, in Patent No. 687 ,060, Perry, which illustr tes a simple form of contactor control, the right hand contactor R in Fig. 4 might be used, as contactor 19 of this application, to open contact 17 and thereby to control the heater circuit, just as in the patent it controls the resistance R. If that contactor B were so used, the heater circuit would be open when the master controller Was in either running position, a, full series or full parallel, and would be closed the rest of the time. In my particular arrangement of contactorcontrol, it will be obvious to anyone skilled in the art, from the above explanation, which contactor may advantageously serve as contactor 19 of this application. It is obvious that if desired the energy supply for the anode heating circuit may be entirely independent from the rectifier circuit. I Energy may be supplied from the transformer directly, or from a storage battery. By supplying the heating circuit from the rectifier itself, however, the arc may be kept alive when the motor circuit is opened. As disclosed in the abovementioned Story patent the heaters may consist of insulated armored ,wire and preferably are operated in mercury so as to insure a uniform temperature at which mercury'will not condense.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. The combination of a current supply circuit, a load device consuming energy intermittently, a vapor electric device in said circuit, and means for automatically maintaining the anode or anodes of the vapor device heated when the load device is idle 2. The combination of a vapor electric device, an energy supplying circuit therefor, a main load device consuming energy intermittently, an auxiliary load device, and means for automatically inserting said auxiliary load device in circuit with the vapor electric device when the main load device is deenergized.

' nating current, a mercury vapor rectifier connected thereto, said rectifier having anodes provided respectively with electric heaters, a load device supplied with direct current by said rectifier and a controller provided with contacts arranged to substitute the anode heating circuit in place of the load device when the load device is deenergized- 5. The combination of a metal-walled, high powered mercury "rectifier having anodes of solidmaterial, means for heating the anodes of said rectifier, a load device taking energy intermittently from said rectifier, and means for automatically energizing said heating means when the load current is reduced below a value insufiicient to maintain the rectifier anodes heated to a temperature at which mercury will not condense thereon. I

In witness whereof, I have hereunto set my hand this 10th day of March 1914.

LAURENCE A. HAWKINS.

/ Witnesses:

E. P. EDWARDS,

HELEN ORFORD. 

